The invention relates to an electrical protection apparatus, formed by association of a circuit breaker and an effector,
the circuit breaker comprising a first switch circuit with stationary and movable contacts, a mechanism controlled by an electromagnetic trip device with operating coil and by a thermal trip device, a pair of first and second arc guiding horns associated with a switching electrode, arranged near the contacts of the first switch circuit, an arc extinguishing chamber in the trip devices circuit, an input terminal, and an output terminal, PA1 the effector having a second switch circuit arranged to be electrically connected in series with said first switch circuit, when the latter is in the closed state, and to be automatically shunted by switching of the arc onto the electrode when the mechanism trips following a fault. PA1 the effector comprises a first connection strip to the stationary contact and a second connection strip to the second guiding horn and switching electrode, PA1 the first guiding horn is connected with the movable contact to the input terminal, PA1 and an insulating gap is arranged between the stationary contact and the switching electrode.
In a known apparatus of the kind mentioned, described in the document EP-A-104,981, the effector is formed by a static switch connected in series with the circuit breaker contacts. In a first embodiment, the switch is connected between the stationary contact and the input terminal, whereas the movable contact is connected to the output terminal by means of the thermal trip device and electromagnetic trip device. The switch remains powered on in the open state of the circuit breaker contacts, and the trip devices, notably the coil of the electromagnetic trip device, are shunted when the arc switches onto the two guiding horns of the arc extinguishing chamber. In the second embodiment, the switch is connected between the trip devices and the output terminal, and the two guiding horns are connected respectively to the input terminal and the output terminal. During tripping of the circuit breaker following a fault, it is necessary to wait until the end of the opening travel of the movable contact for the arc switching to be established enabling shunting of the switch to be achieved. The coil of the electromagnetic trip device is then shunted simultaneously with the switch.